EP0648773B1 - A silacyclohexane compound, a method of preparing it and a liquid crystal composition containing it - Google Patents

A silacyclohexane compound, a method of preparing it and a liquid crystal composition containing it Download PDF

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EP0648773B1
EP0648773B1 EP94116195A EP94116195A EP0648773B1 EP 0648773 B1 EP0648773 B1 EP 0648773B1 EP 94116195 A EP94116195 A EP 94116195A EP 94116195 A EP94116195 A EP 94116195A EP 0648773 B1 EP0648773 B1 EP 0648773B1
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silacyclohexane
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EP0648773A1 (en
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Takeshi C/O Speciality Chem Research Cen Kinsho
Tatsushi C/O Speciality Chem Research Cen Kaneko
Takaaki C/O Speciality Chem Research Cen Shimizu
Tsutomu C/O Speciality Chem Research Cen Ogihara
Ryuichi C/O Speciality Chem Research Ce Saito
Hideshi C/O Corp.Research Center Kurihara
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Shin Etsu Chemical Co Ltd
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    • C—CHEMISTRY; METALLURGY
    • C07—ORGANIC CHEMISTRY
    • C07F—ACYCLIC, CARBOCYCLIC OR HETEROCYCLIC COMPOUNDS CONTAINING ELEMENTS OTHER THAN CARBON, HYDROGEN, HALOGEN, OXYGEN, NITROGEN, SULFUR, SELENIUM OR TELLURIUM
    • C07F7/00—Compounds containing elements of Groups 4 or 14 of the Periodic System
    • C—CHEMISTRY; METALLURGY
    • C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
    • C09K—MATERIALS FOR MISCELLANEOUS APPLICATIONS, NOT PROVIDED FOR ELSEWHERE
    • C09K19/00—Liquid crystal materials
    • C09K19/04—Liquid crystal materials characterised by the chemical structure of the liquid crystal components, e.g. by a specific unit
    • C09K19/40—Liquid crystal materials characterised by the chemical structure of the liquid crystal components, e.g. by a specific unit containing elements other than carbon, hydrogen, halogen, oxygen, nitrogen or sulfur, e.g. silicon, metals
    • C09K19/406—Liquid crystal materials characterised by the chemical structure of the liquid crystal components, e.g. by a specific unit containing elements other than carbon, hydrogen, halogen, oxygen, nitrogen or sulfur, e.g. silicon, metals containing silicon
    • C—CHEMISTRY; METALLURGY
    • C07—ORGANIC CHEMISTRY
    • C07F—ACYCLIC, CARBOCYCLIC OR HETEROCYCLIC COMPOUNDS CONTAINING ELEMENTS OTHER THAN CARBON, HYDROGEN, HALOGEN, OXYGEN, NITROGEN, SULFUR, SELENIUM OR TELLURIUM
    • C07F7/00—Compounds containing elements of Groups 4 or 14 of the Periodic System
    • C07F7/02—Silicon compounds
    • C07F7/08—Compounds having one or more C—Si linkages
    • C07F7/0803—Compounds with Si-C or Si-Si linkages
    • C07F7/081—Compounds with Si-C or Si-Si linkages comprising at least one atom selected from the elements N, O, halogen, S, Se or Te
    • C—CHEMISTRY; METALLURGY
    • C07—ORGANIC CHEMISTRY
    • C07F—ACYCLIC, CARBOCYCLIC OR HETEROCYCLIC COMPOUNDS CONTAINING ELEMENTS OTHER THAN CARBON, HYDROGEN, HALOGEN, OXYGEN, NITROGEN, SULFUR, SELENIUM OR TELLURIUM
    • C07F7/00—Compounds containing elements of Groups 4 or 14 of the Periodic System
    • C07F7/02—Silicon compounds
    • C07F7/08—Compounds having one or more C—Si linkages
    • C07F7/0896—Compounds with a Si-H linkage
    • C—CHEMISTRY; METALLURGY
    • C07—ORGANIC CHEMISTRY
    • C07F—ACYCLIC, CARBOCYCLIC OR HETEROCYCLIC COMPOUNDS CONTAINING ELEMENTS OTHER THAN CARBON, HYDROGEN, HALOGEN, OXYGEN, NITROGEN, SULFUR, SELENIUM OR TELLURIUM
    • C07F7/00—Compounds containing elements of Groups 4 or 14 of the Periodic System
    • C07F7/02—Silicon compounds
    • C07F7/08—Compounds having one or more C—Si linkages
    • C07F7/12—Organo silicon halides
    • C—CHEMISTRY; METALLURGY
    • C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
    • C09K—MATERIALS FOR MISCELLANEOUS APPLICATIONS, NOT PROVIDED FOR ELSEWHERE
    • C09K19/00—Liquid crystal materials
    • C09K19/04—Liquid crystal materials characterised by the chemical structure of the liquid crystal components, e.g. by a specific unit
    • C09K19/40—Liquid crystal materials characterised by the chemical structure of the liquid crystal components, e.g. by a specific unit containing elements other than carbon, hydrogen, halogen, oxygen, nitrogen or sulfur, e.g. silicon, metals

Definitions

  • This invention relates to a new silacyclohexane compound, a method of preparing it, and a liquid crystal composition which contains it as well as a liquid crystal display element which contains said liquid crystal composition.
  • a liquid crystal display element utilizes the optical anisotropy and dielectric anisotropy of liquid crystal substances.
  • Display methods include the TN mode (twisted nematic mode), the STN mode (super twisted nematic mode), the SBE mode (super birefringence mode), the DS mode (dynamic scattering mode), the guest-host mode, the DAP mode ("deformation of aligned phase” mode) and the OMI mode (optical mode interference mode).
  • the most common display device has a twisted nematic structure based on the Schadt-Helfrich mode.
  • liquid crystal substance used in these liquid crystal displays are somewhat different depending on the display mode. However, a wide liquid crystal temperature range and stability against moisture, air, light, heat, electric fields, etc. are commonly required in all display methods. Furthermore, it is desirable for the liquid crystal material to have a low viscosity, and also to have a short address time, low threshold voltage and high contrast in the cell(s).
  • liquid crystal mixtures are obtained by mixing several to more than ten liquid crystal compounds and liquid crystal like compounds. Because of this, it is also important that components of a liquid crystal composition mix easily each other.
  • liquid crystal compounds which can be components for these
  • one of the basic components conventionally known which controls the electro-optical performance is a compound which has a so-called cyclohexyl ring-ethylene-cyclohexyl ring -phenyl ring structure (CECP structure) such as those shown by the fallowing general formulas:
  • this invention is a newly developed liquid crystal substance targeting improvement in characteristics of liquid crystal substances, and its object is to provide a liquid crystal compound containing silacyclohexane rings, which is completely different from the conventional liquid crystal compounds with the cyclohexyl ring-ethylene-cyclohexyl ring-phenyl ring structure (CECP structure).
  • CECP structure cyclohexyl ring-ethylene-cyclohexyl ring-phenyl ring structure
  • This invention provides a silacyclohexane compound represented by the following general formula (I).
  • R denotes hydrogen, a linear-chain alkyl group with a carbon number of 1-10, a branched-chain alkyl group with a carbon number of 3-8, an alkoxyalkyl group with a carbon number of 2-7, a floroalkyl group with a carbon number of 1-10 in which one or two hydrogen atoms are substituted by florine atom(s), or an alkenyl group with a carbon number of 2-8.
  • X denotes a CN, F, Cl, CF 3 , CF 2 Cl, CHFCl, OCF 3 , OCHF 2 , OCF 2 Cl, OCHFCl, R or OR group (R is the same as defined in the general formula (1).
  • Y denotes H or F.
  • Z denotes H or F.
  • This invention also provides a method of preparing the silacyclohexane compound represented by the general formula (I) characterized by carbon-carbon bond formation or carbon -silicon bond formation using a specific organometallic reagent.
  • the preparing methods are listed below.
  • M denotes MgP (P denotes a halogen atom), ZnP or Li.
  • R denotes hydrogen, a linear-chain alkyl group with a carbon number of 1-10, a branched-chain alkyl group with a carbon number of 3-8, an alkoxyalkyl group with a carbon number of 2-7, a floroalkyl group with a carbon number of 1-10 in which one or two hydrogen atoms are substituted by florine atom(s), or an alkenyl group with a carbon number of 2-8.
  • Q denotes a halogen atom, or an alkoxy, methanesulfonyl, benzenesulfonyl or p-toluenesulfonyl group.
  • X denotes a CN, F, Cl, CF 3 , CF 2 Cl, CHFCl, OCF 3 , OCHF 2 , OCF 2 Cl, OCHFCl, R or OR group.
  • Y denotes H or F.
  • Z denotes H or F.
  • M denotes MgP (P denotes a halogen atom), ZnP or Li.
  • R denotes hydrogen, a linear-chain alkyl group with a carbon number of 1-10, a branched-chain alkyl group with a carbon number of 3-8, an alkoxyalkyl group with a carbon number of 2-7, a floroalkyl group with a carbon number of 1-10 in which one or two hydrogen atoms are substituted by florine atom(s), or an alkenyl group with a carbon number of 2-8.
  • Q denotes a halogen atom, alkoxy, methanesulfonyl, benzenesulfonyl or p-toluenesulfonyl group.
  • X denotes a CN, F, Cl, CF 3 , CF 2 Cl, CHFCl, OCF 3 , OCHF 2 , OCF 2 Cl, OCHFCl, R or OR group.
  • Y denotes H or F.
  • Z denotes H or F.
  • M denotes MgP (P denotes a halogen atom), ZnP or Li.
  • R denotes hydrogen, a linear-chain alkyl group with a carbon number of 1-10, a branched-chain alkyl group with a carbon number of 3-8, an alkoxyalkyl group with a carbon number of 2-7, a floroalkyl group with a carbon number of 1-10 in which one or two hydrogen atoms are substituted by florine atom(s), or an alkenyl group with a carbon number of 2-8.
  • Q denotes a halogen atom, or an alkoxy, methanesulfonyl, benzenesulfonyl or p-toluenesulfonyl group.
  • X denotes a CN, F, Cl, CF 3 , CF 2 Cl, CHFCl, OCF 3 , OCHF 2 , OCF 2 Cl, OCHFCl, R or OR group.
  • Y denotes H or F.
  • Z denotes H or F.
  • M denotes MgP (P denotes a halogen atom), ZnP or Li.
  • R denotes hydrogen, a linear-chain alkyl group with a carbon number of 1-10, a branched-chain alkyl group with a carbon number of 3-8, an alkoxyalkyl group with a carbon number of 2-7, a floroalkyl group with a carbon number of 1-10 in which one or two hydrogen atoms are substituted by florine atom(s), or an alkenyl group with a carbon number of 2-8.
  • Q denotes a halogen atom, or an alkoxy, methanesulfonyl, benzenesulfonyl or p-toluenesulfonyl group.
  • X denotes a CN, F, Cl, CF 3 , CF 2 Cl, CHFCl, OCF 3 , OCHF 2 , OCF 2 Cl, OCHFCl, R or OR group.
  • Y denotes H or F.
  • Z denotes H or F.
  • M' denotes MgP (P denotes a halogen atom), ZnP or B(OY') (Y' denotes H or an alkyl group).
  • R denotes hydrogen, a linear-chain alkyl group with a carbon number of 1-10, a branched-chain alkyl group with a carbon number of 3-8, an alkoxyalkyl group with a carbon number of 2-7, a floroalkyl group with a carbon number of 1-10 in which one or two hydrogen atoms are substituted by florine atom(s), or an alkenyl group with a carbon number of 2-8.
  • Q denotes a halogen atom, alkoxy, methanesulfonyl, benzenesulfonyl or p-toluenesulfonyl group.
  • X denotes a CN, F, Cl, CF 3 , CF 2 Cl, CHFCl, OCF 3 , OCHF 2 , OCF 2 Cl, OCHFCl, R or OR group.
  • Y denotes H or F.
  • Z denotes H or F.
  • this invention is a liquid crystal composition characterized by containing the compound represented by the general formula (I) as shown above, as well as a liquid crystal display element using this liquid crystal composition.
  • the new compounds represented by the general formula (I) are silacyclohexane compounds whose ring structure has at least one trans-1 or 4-trans-silacyclohexane ring, specifically represented by the ring structures shown below:
  • R denotes: a linear-chain alkyl group with a carbon number of 1-10, i.e. a methyl, ethyl, n -propyl, n-butyl, n-pentyl, n-hexyl, n-heptyl, n-octyl, n-nonyl or n-decyl group; or a branched-chain alkyl group with a carbon number of 3-8, i.e.
  • W, W 1 and W 2 independently from each other, denote H, F, Cl or CH 3 .
  • X denotes a CN, F, Cl, CF 3 , CF 2 Cl, CHFCl, OCF 3 , OCHF 2 , OCF 2 Cl, OCHFCl, R or OR group.
  • Y denotes H or F.
  • Z denotes H or F.
  • the ring structure specifically denotes, for example, the following groups:
  • R the following groups are desirable for practical use: a linear-chain alkyl group with a carbon number of 2-7, i.e. an ethyl, n-propyl, n-butyl, n-pentyl, n-hexyl or n -heptyl group; or some branched-chain alkyl groups with a carbon number of 3-7 including isopropyl, 1-methylpropyl, 2 -methylpropyl, 1-methylbutyl, 2-methylbutyl, 3-methylbutyl, 1-methylpentyl, 2-methylpentyl and 2-ethylhexyl groups; or an alkoxyalkyl group with a carbon number of 2-6, i.e.
  • H, F and CH 3 groups are desirable in practical use for W, W 1 and W 2 .
  • the groups are desirable in practical use for the ring structure
  • These compounds are prepared by carbon-carbon bond formation or carbon-silicon bond formation between an organometallic reagent and a compound which has an eliminatable group(s) such as a halogen atom, alkoxy, methanesulfonyl, benzenesulfonyl or p-toluenesulfonyl group. Methods of preparing these compounds are described in detail below.
  • M denotes MgP (P denotes a halogen atom), ZnP or Li.
  • R denotes hydrogen, a linear-chain alkyl group with a carbon number of 1-10, a branched -chain alkyl group with a carbon number of 3-8, an alkoxyalkyl group with a carbon number of 2-7, a floroalkyl group with a carbon number of 1-10 in which one or two hydrogen atoms are are substituted by florine atom(s), or an alkenyl group with a carbon number of 2-8.
  • Q denotes a halogen atom, alkoxy, methanesulfonyl, benzenesulfonyl or p-toluenesulfonyl group.
  • X denotes a CN, F, Cl, CF 3 , CF 2 Cl, CHFCl, OCF 3 , OCHF 2 , OCF 2 Cl, OCHFCl, R or OR group.
  • Y denotes H or F.
  • Z denotes H or F.
  • Q is a halogen atom or an alkoxy group.
  • Q is a Cl or Br atom, or an OCH 3 or OCH 2 CH 3 group, then the carbon-silicon bond formation reaction proceeds easily and gives a high yield of the target product.
  • Q is a halogen atom or a methanesulfonyl, benzenesulfonyl or p-toluenesulfonyl group. It is particularly preferable if Q is Br or I, because then the target product can be obtained with a high yield.
  • M denotes MgP (P denotes a halogen atom), ZnP or Li.
  • R denotes hydrogen, a linear-chain alkyl group with a carbon number of 1-10, a branched -chain alkyl group with a carbon number of 3-8, an alkoxyalkyl group with a carbon number of 2-7, a floroalkyl group with a carbon number of 1-10 in which one or two hydrogen atoms are substituted by florine atom(s), or an alkenyl group with a carbon number of 2-8.
  • Q denotes a halogen atom, alkoxy, methanesulfonyl, benzenesulfonyl or p-toluenesulfonyl group.
  • X denotes a CN, F, Cl, CF 3 , CF 2 Cl, CHFCl, OCF 3 , OCHF 2 , OCF 2 Cl OCHFCl, R or OR group.
  • Y denotes H or F.
  • Z denotes H or F.
  • the carbon-carbon bond formation reaction is carried out in the presence of a catalytic quantity of a copper salt.
  • a halogen atom or a methanesulfonyl, benzensulfonyl or p-toluenesulfonyl group can be used. Particularly preferable are Br, I and the p-toluenesulfonyl group because they give a higher yield of the target product.
  • M denotes MgP (P denotes a halogen atom), ZnP or Li.
  • R denotes hydrogen, a linear-chain alkyl group with a carbon number of 1-10, a branched -chain alkyl group with a carbon number of 3-8, an alkoxyalkyl group with a carbon number of 2-7, a floroalkyl group with a carbon number of 1-10 in which one or two hydrogen atoms are substituted by florine atom(s), or an alkenyl group with a carbon number of 2-8.
  • Q denotes a halogen atom, or an alkoxy, methanesulfonyl, benzenesulfonyl or p-toluenesulfonyl group.
  • X denotes a CN, F, Cl, CF 3 , CF 2 Cl, CHFCl, OCF 3 , OCHF 2 , OCF 2 Cl, OCHFCl, R or OR group.
  • Y denotes H or F.
  • Z denotes H or F.
  • Q is a halogen atom or an alkoxy group. It is particularly preferable if Q is a Cl or Br atom, or an OCH 3 or OCH 2 CH 3 group, because then the carbon -silicon bond formation reaction proceeds easily and gives a high yield of the target product.
  • Q is a halogen atom or a methanesulfonyl, benzenesulfonyl or p-toluenesulfonyl group. It is particularly preferable if Q is Br , I or the p-toluenesulfonyl group, because then the target product can be obtained with a high yield.
  • M' denotes MgP (P denotes a halogen atom), ZnP or B(OY') (Y' denotes H or an alkyl group).
  • R denotes hydrogen, a linear-chain alkyl group with a carbon number of 1-10, a branched-chain alkyl group with a carbon number of 3-8, an alkoxyalkyl group with a carbon number of 2-7, a fluoroalkyl group with a carbon number of 1-10 in which one or two hydrogen atoms are substituted by florine atom(s), or an alkenyl group with a carbon number of 2-8.
  • Q denotes a halogen atom, or an alkoxy, methanesulfonyl or p-toluenesulfonyl group.
  • X denotes a CN, F, Cl, CF 3 , CF 2 Cl, CHFCl, OCF 3 , OCHF 2 , OCF 2 Cl, OCHFCl R or OR group.
  • Y denotes H or F.
  • Z denotes H or F. ⁇
  • This reaction is carried out in the presence of a transition metal catalyst.
  • Palladium compounds and nickel compounds are particularly preferable for the catalyst.
  • Q is a halogen atom or a methanesulfonyl, benzenesulfonyl or p-toluenesulfonyl group. Particularly preferable are Cl, Br and I because they give a higher yield of the target product.
  • the compound produced here may be a mixture of trans isomers and cis isomers in terms of the conformation of the silacyclohexane ring. If this is the case, then a conventional purification means such as chromatography and recrystallization is employed to separate and purify the trans isomers to obtain the silacyclohexane compound of this invention represented by the general formula (I).
  • the silacyclohexane compound of this invention can be mixed with known compounds to obtain a liquid crystal composition.
  • the compound used for mixing to obtain the liquid crystal compound can be chosen from among the known compounds shown below:
  • the ratio of one or more types of the silacyclohexane compound of this invention contained in the liquid crystal composition is preferably 1-50 wt%, more preferably 5-30 wt%.
  • the liquid crystal composition can also contain a polygenetic dye(s) to generate the colored guest-host system and additives to change the dielectric anisotropy, viscosity and the orientation of the nematic phase.
  • the liquid crystal composition thus formed can be used to manufacture various liquid crystal display elements in conventional methods. That is, the liquid crystal composition containing the silacyclohexane compound of this invention is sealed between transparent plates which have electrodes of desired shapes and thus used as liquid crystal display elements. These elements can have various undercoatings, overcoatings for orientation control, a polarizer plate(s), a filter(s) and a reflector layer(s), as necessary. They can be made into a laminated cell or combined with other display elements. Semiconductor substrates and light sources can also be used to make various types of displays.
  • DSM dynamic scattering
  • TN twisted nematic
  • GH guest-host
  • STN super twisted nematic
  • PDLC polymer dispersion liquid crystal
  • this product exhibited the nematic phase in the temperature range of 11.2°C-63.5°C, and that the temperature range of the nematic phase was extended significantly on the low temperature end compared with the existing trans-4-(2-(trans-4-(3,4-difluorophenyl)cyclohexyl) ethyl)-1-n-propyl-1-cyclohexane (C-N transition temperature 36.0°C).
  • the preparation was conducted in the same manner as in Example 1, except that 4.1 g (10 mmol) of 1,1-difluoro-4 -(2-(trans-4-(p-trifluoromethoxyphenyl)cyclohexyl)ethyl-1-silacyclohexane was used instead of 3.7 g (10 mmol) of 1-chloro -4-(2-(trans-4-(3,4-difluorophenyl)cyclohexyl)ethyl)-1-silacyclohexane.
  • the preparation was conducted in the same manner as in Example 1, except that 3.9 g(10 mmol) of 1-chloro-4-(2-(trans -4-(p-trifluoromethoxyphenyl)cyclohexyl)ethyl)-1-silacyclohexane was used instead of 3.7 g (10 mmol) of 1-chloro-4-(2-(trans -4-(3,4-difluorophenyl)cyclohexyl)ethyl)-1-silacyclohexane.
  • the preparation was conducted in the same manner as in Example 1, except that 3.7 g(10 mmol) of 1-chloro-4-(2-(trans -4-(4-chloro-3-fluorophenyl)cyclohexyl)ethyl-1-silacyclohexane was used instead of 3.7 g (10 mmol) of 1-chloro-4-(2-(trans -4-(3,4-difluorophenyl)cyclohexyl)ethyl)-1-silacyclohexane.
  • the preparation was conducted in the same manner as in Example 22, except that 18.7 g (50 mmol) of (trans-4-(p-methoxyphenyl)cyclohexyl)methyl p-toluenesulfonate and (trans -4-n-pentyl-4-silacyclohexyl)methylmagnesium bromide were used instead of 18.1 g (50 mmol) of (trans-4-(p-fluorophenyl) cyclohexyl)methyl p-toluenesulfonate and (trans-4-n-propyl-4-silacyclohexyl)methylmagnesium bromide.
  • the preparation was conducted in the same manner as in Example 22, except that 18.9 g (50 mmol) of (trans-4-(p-fluorophenyl)-1-silacyclohexyl)methyl p-toluenesulfonate and (trans-4-n-pentyl-4-silacyclohexyl)methylmagnesium bromide were used instead of 18.1 g (50 mmol) of (trans-4-(p-fluorophenyl) cyclohexyl)methyl p-toluenesulfonate and (trans-4-n-propyl-4-silacyclohexyl)methylmagnesium bromide.
  • the preparation was conducted in the same manner as in Example 26, except that 11.2 g (50 mmol) of trans-4-(p-fluorophenyl) -1-methoxy-1-silacyclohexane and 2-(trans-4-n-butylcyclohexyl) ethyl lithium were used instead of 10.0 g (50 mmol) of 1-methoxy -4-n-pentyl-1-silacyclohexane and 2-(trans-4-(3,4-difluorophenyl) cyclohexyl)ethyl lithium.
  • the preparation was conducted in the same manner as in Example 26, except that 11.2 g (50 mmol) of trans-4-(p-fluorophenyl) -1-methoxy-1-silacyclohexane and 2-(trans-4-n-pentylcyclohexyl) ethyl lithium were used instead of 10.0 g (50 mmol) of 1-methoxy -4-n-pentyl-1-silacyclohexane and 2-(trans-4-(3,4-difluorophenyl) cyclohexyl)ethyl lithium.
  • the preparation was conducted in the same manner as in Example 30, except that 5.9 g (19.9 mmol) of trans-1-iodomethyl -4-n-pentylcyclohexane and (4-(3,4-difluorophenyl)-1-silacyclohexyl) methylmagnesium chloride were used instead of 4.5 g (19.9 mmol) of trans-1-iodomethyl-4-n-propylcyclohexane and (4-(p-fluorophenyl) -1-silacyclohexyl)methylmagnesium chloride.
  • the preparation was conducted in the same manner as in Example 30, except that 6.3 g (19.9 mmol) of trans-1-iodomethyl -4-(p-fluorophenyl)cyclohexane and (4-n-isobutyl-1-silacyclohexyl) methylmagnesium chloride were used instead of 4.5 g (19.9 mmol) of trans-1-iodomethyl-4-n-propylcyclohexane and (4-(p-fluorophenyl) -1-silacyclohexyl)methylmagnesium chloride.
  • the silacyclohexane rings of the target product thus obtained were a mixture of trans isomers and cis isomers. Following a conventional after treatment, they were separated by means of chromatography to obtain 2.0 g of the trans isomers of the target product (yield64%).
  • the compounds of this invention obtained in the examples described above were added to existing liquid crystal compositions to prepare liquid crystal compositions of this invention.
  • the transition temperature(s) and the threshold voltage at 25°C were measured for the obtained liquid crystal compositions.
  • Mixture A comprising 43 mole% of trans-4-(2-(trans-4 -(3,4-difluorophenyl)cyclohexyl)ethyl)-1-ethyl-1-silacyclohexane, 17 mole% of trans-4-(2-(trans-4-(3,4-difluorophenyl)cyclohexyl) ethyl)-1-n-propyl-1-silacyclohexane and 40 mole% of trans-4 -(2-(trans-4-(3,4-difluorophenyl)cyclohexyl)ethyl)-1-pentyl -1-silacyclohexane exhibited the following characteristics:
  • liquid crystal compounds of this invention which have Si as a ring composing element have the following advantages over liquid crystal compounds which have a conventional CECP structure comprising similar hydrocarbon rings:
  • liquid crystal compounds whose X in the general formula (I) is neither R nor OR have, in addition to the advantages mentioned above, the effect of lowering the threshold voltage because of a greater dielectric anisotropy.
  • the liquid crystal compounds of this invention can be widely used as the base material which comprises the major component of the liquid crystal phase, in a manner similar to how the conventional liquid crystal compounds with a CECP structure of similar hydrocarbon rings are used.
  • the liquid crystal compound whose substitutional group X in the general formula (I) is R or OR has negative or near-zero dielectric anisotropy, and therefore it should preferably be used for the liquid crystal phase for display based on the dynamic scattering (DS), guest -host (GH) or deformation of aligned phase (DAP mode).
  • the compounds in which X is other than these should preferably be used for manufacturing the liquid crystal phase with a large positive dielectric anisotropy which is used in display elements based on the twisted nematic cell or the cholesteric-nematic phase transition.

Description

BACKGROUND OF THE INVENTION 1. Field of the invention
This invention relates to a new silacyclohexane compound, a method of preparing it, and a liquid crystal composition which contains it as well as a liquid crystal display element which contains said liquid crystal composition.
2. The Prior Art
A liquid crystal display element utilizes the optical anisotropy and dielectric anisotropy of liquid crystal substances. Display methods include the TN mode (twisted nematic mode), the STN mode (super twisted nematic mode), the SBE mode (super birefringence mode), the DS mode (dynamic scattering mode), the guest-host mode, the DAP mode ("deformation of aligned phase" mode) and the OMI mode (optical mode interference mode). The most common display device has a twisted nematic structure based on the Schadt-Helfrich mode.
Properties required of the liquid crystal substance used in these liquid crystal displays are somewhat different depending on the display mode. However, a wide liquid crystal temperature range and stability against moisture, air, light, heat, electric fields, etc. are commonly required in all display methods. Furthermore, it is desirable for the liquid crystal material to have a low viscosity, and also to have a short address time, low threshold voltage and high contrast in the cell(s).
Currently, there is no single compound which satisfies all of these requirements. In practice, liquid crystal mixtures are obtained by mixing several to more than ten liquid crystal compounds and liquid crystal like compounds. Because of this, it is also important that components of a liquid crystal composition mix easily each other.
Among liquid crystal compounds which can be components for these, one of the basic components conventionally known which controls the electro-optical performance is a compound which has a so-called cyclohexyl ring-ethylene-cyclohexyl ring -phenyl ring structure (CECP structure) such as those shown by the fallowing general formulas:
Figure 00020001
Figure 00030001
In recent years, along with the expansion of the applications of liquid crystal displays, the characteristics required of liquid crystal materials are becoming more and more advanced and demanding. In particular, superior characteristics such as a lower driving voltage, a wider temperature range for automobile onboard use and improved low temperature performance, compared with conventional liquid crystal substances, are desired.
BRIEF SUMMARY OF THE INVENTION
From such a viewpoint, this invention is a newly developed liquid crystal substance targeting improvement in characteristics of liquid crystal substances, and its object is to provide a liquid crystal compound containing silacyclohexane rings, which is completely different from the conventional liquid crystal compounds with the cyclohexyl ring-ethylene-cyclohexyl ring-phenyl ring structure (CECP structure).
This invention provides a silacyclohexane compound represented by the following general formula (I).
Figure 00040001
In this formula, R denotes hydrogen, a linear-chain alkyl group with a carbon number of 1-10, a branched-chain alkyl group with a carbon number of 3-8, an alkoxyalkyl group with a carbon number of 2-7, a floroalkyl group with a carbon number of 1-10 in which one or two hydrogen atoms are substituted by florine atom(s), or an alkenyl group with a carbon number of 2-8. For the groups
Figure 00050001
at least one of these is a trans-1-sila-1,4-cyclohexylene or trans-4-sila-1,4-cyclohexylene group whose silicon at position 1 or position 4 has a substitutional group(s) of H, F, Cl or CH3, and the other denotes a trans-1,4-cyclohexylene group. X denotes a CN, F, Cl, CF3, CF2Cl, CHFCl, OCF3, OCHF2, OCF2Cl, OCHFCl, R or OR group (R is the same as defined in the general formula (1). Y denotes H or F. Z denotes H or F.
This invention also provides a method of preparing the silacyclohexane compound represented by the general formula (I) characterized by carbon-carbon bond formation or carbon -silicon bond formation using a specific organometallic reagent. The preparing methods are listed below.
A method of preparing a silacyclohexane compound using a reaction between an organometallic reagent R-M and a compound
Figure 00060001
In this formula, M denotes MgP (P denotes a halogen atom), ZnP or Li. R denotes hydrogen, a linear-chain alkyl group with a carbon number of 1-10, a branched-chain alkyl group with a carbon number of 3-8, an alkoxyalkyl group with a carbon number of 2-7, a floroalkyl group with a carbon number of 1-10 in which one or two hydrogen atoms are substituted by florine atom(s), or an alkenyl group with a carbon number of 2-8. Q denotes a halogen atom, or an alkoxy, methanesulfonyl, benzenesulfonyl or p-toluenesulfonyl group. X denotes a CN, F, Cl, CF3, CF2Cl, CHFCl, OCF3, OCHF2, OCF2Cl, OCHFCl, R or OR group. Y denotes H or F. Z denotes H or F.
A method of preparing a silacyclohexane compound using a reaction between an organometallic reagent
Figure 00060002
and a compound
Figure 00070001
In this formula, M denotes MgP (P denotes a halogen atom), ZnP or Li. R denotes hydrogen, a linear-chain alkyl group with a carbon number of 1-10, a branched-chain alkyl group with a carbon number of 3-8, an alkoxyalkyl group with a carbon number of 2-7, a floroalkyl group with a carbon number of 1-10 in which one or two hydrogen atoms are substituted by florine atom(s), or an alkenyl group with a carbon number of 2-8. Q denotes a halogen atom, alkoxy, methanesulfonyl, benzenesulfonyl or p-toluenesulfonyl group. X denotes a CN, F, Cl, CF3, CF2Cl, CHFCl, OCF3, OCHF2, OCF2Cl, OCHFCl, R or OR group. Y denotes H or F. Z denotes H or F. n and m are integers 0, 1 or 2 (where n+m = 2).
A method of preparing a silacyclohexane compound using a reaction between an organometallic reagent
Figure 00070002
and a compound
Figure 00080001
In this formula, M denotes MgP (P denotes a halogen atom), ZnP or Li. R denotes hydrogen, a linear-chain alkyl group with a carbon number of 1-10, a branched-chain alkyl group with a carbon number of 3-8, an alkoxyalkyl group with a carbon number of 2-7, a floroalkyl group with a carbon number of 1-10 in which one or two hydrogen atoms are substituted by florine atom(s), or an alkenyl group with a carbon number of 2-8. Q denotes a halogen atom, or an alkoxy, methanesulfonyl, benzenesulfonyl or p-toluenesulfonyl group. X denotes a CN, F, Cl, CF3, CF2Cl, CHFCl, OCF3, OCHF2, OCF2Cl, OCHFCl, R or OR group. Y denotes H or F. Z denotes H or F. n and m are integers 0, 1 or 2 (where n+m = 2).
A method of preparing a silacyclohexane compound using a reaction between an organometallic reagent
Figure 00080002
and a compound
Figure 00080003
In this formula, M denotes MgP (P denotes a halogen atom), ZnP or Li. R denotes hydrogen, a linear-chain alkyl group with a carbon number of 1-10, a branched-chain alkyl group with a carbon number of 3-8, an alkoxyalkyl group with a carbon number of 2-7, a floroalkyl group with a carbon number of 1-10 in which one or two hydrogen atoms are substituted by florine atom(s), or an alkenyl group with a carbon number of 2-8. Q denotes a halogen atom, or an alkoxy, methanesulfonyl, benzenesulfonyl or p-toluenesulfonyl group. X denotes a CN, F, Cl, CF3, CF2Cl, CHFCl, OCF3, OCHF2, OCF2Cl, OCHFCl, R or OR group. Y denotes H or F. Z denotes H or F.
A method of preparing a silacyclohexane compound using a reaction between an organometallic reagent
Figure 00090001
and a compound
Figure 00090002
In these formulas, M' denotes MgP (P denotes a halogen atom), ZnP or B(OY') (Y' denotes H or an alkyl group). R denotes hydrogen, a linear-chain alkyl group with a carbon number of 1-10, a branched-chain alkyl group with a carbon number of 3-8, an alkoxyalkyl group with a carbon number of 2-7, a floroalkyl group with a carbon number of 1-10 in which one or two hydrogen atoms are substituted by florine atom(s), or an alkenyl group with a carbon number of 2-8. Q denotes a halogen atom, alkoxy, methanesulfonyl, benzenesulfonyl or p-toluenesulfonyl group. X denotes a CN, F, Cl, CF3, CF2Cl, CHFCl, OCF3, OCHF2, OCF2Cl, OCHFCl, R or OR group. Y denotes H or F. Z denotes H or F.
Furthermore, this invention is a liquid crystal composition characterized by containing the compound represented by the general formula (I) as shown above, as well as a liquid crystal display element using this liquid crystal composition.
The new compounds represented by the general formula (I) are silacyclohexane compounds whose ring structure has at least one trans-1 or 4-trans-silacyclohexane ring, specifically represented by the ring structures shown below:
Figure 00100001
Figure 00110001
Figure 00120001
In these formulas, R denotes: a linear-chain alkyl group with a carbon number of 1-10, i.e. a methyl, ethyl, n -propyl, n-butyl, n-pentyl, n-hexyl, n-heptyl, n-octyl, n-nonyl or n-decyl group; or a branched-chain alkyl group with a carbon number of 3-8, i.e. isopropyl, sec-butyl, isobutyl, 1-methylbutyl, 2-methylbutyl, 3-methylbutyl, 1-methylpentyl, 2-methylpentyl, 3-methylpentyl, 1-ethylpentyl, 1-methylhexyl, 2-methylhexyl, 3-methylhexyl, 2-ethylhexyl, 3-ethylhexyl, 1-methylheptyl, 2-methylheptyl or 3-methylheptyl group; or an alkoxyalkyl group with a carbon number of 2-7, i.e. a methoxymethyl, ethoxymethyl, propoxymethyl, butoxymethyl, pentoxymethyl, hexyloxymethyl, methoxyethyl, ethoxyethyl, propoxyethyl, butoxyethyl, pentoxyethyl, methoxypropyl, ethoxypropyl, propoxypropyl, butoxypropyl, methoxybutyl, ethoxybutyl, propoxybutyl, methoxypentyl or ethoxypentyl group; or a floroalkyl group with a carbon number of 1-10 in which one or two hydrogen atoms are substituted by florine atoms(s), i.e. a 1-floroethyl, 1-floropropyl, 1-florobutyl, 1-floropentyl, 2-floroethyl, 2-floropropyl, 2-florobutyl, 2-floropentyl, 3 -floropropyl, 3-florobutyl, 3-floropentyl, 4-florobutyl, 4-floropentyl, 5-floropentyl, 1,1-difloroethyl, 1,1-difloropropyl, 1,1-diflorobutyl, 1,1-difloropentyl, 2,2-difloroethyl, 2,2-difloropropyl, 2,2 -diflorobutyl, 2,2-difloropentyl, 3,3-difloropropyl, 3,3-diflorobutyl, 3,3-difloropentyl, 4,4-diflorobutyl, 4,4-difloropentyl or 5, 5-difloropentyl group; or an alkenyl group with a carbon number of 2-8, i.e. a vinyl, 1-propenyl, allyl, 1-butenyl, 3-butenyl, isoprenyl, 1-pentenyl, 3-pentenyl, 4-pentenyl dimethylallyl, 1-hexenyl, 3-hexenyl, 5-hexenyl, 1-heptenyl, 3-heptenyl, 6-heptenyl or 7-octenyl group.
W, W1 and W2, independently from each other, denote H, F, Cl or CH3.
X denotes a CN, F, Cl, CF3, CF2Cl, CHFCl, OCF3, OCHF2, OCF2Cl, OCHFCl, R or OR group. Y denotes H or F. Z denotes H or F.
The ring structure
Figure 00130001
specifically denotes, for example, the following groups:
Figure 00130002
Figure 00140001
Figure 00150001
Figure 00160001
Figure 00170001
Figure 00180001
Figure 00190001
Of these, as far as the ring structure is concerned, compounds
Figure 00190002
Figure 00200001
are desirable for practical use.
For R, the following groups are desirable for practical use: a linear-chain alkyl group with a carbon number of 2-7, i.e. an ethyl, n-propyl, n-butyl, n-pentyl, n-hexyl or n -heptyl group; or some branched-chain alkyl groups with a carbon number of 3-7 including isopropyl, 1-methylpropyl, 2 -methylpropyl, 1-methylbutyl, 2-methylbutyl, 3-methylbutyl, 1-methylpentyl, 2-methylpentyl and 2-ethylhexyl groups; or an alkoxyalkyl group with a carbon number of 2-6, i.e. a methoxymethyl, methoxyethyl, methoxypropyl, methoxypentyl, ethoxymethyl, ethoxyethyl, propoxymethyl or pentoxymethyl group; or some floroalkyl groups with a carbon number of 1-10 in which one or two hydrogen atoms are substituted by florine atom(s) including 2-floroethyl, 2-floropropyl, 4-florobutyl, 4-floropentyl, 5-floropentyl, 1, 1-difloroethyl, 2,2-difloroethyl, 2,2-difloropropyl, 2,2-diflorobutyl, 4,4-diflorobutyl and 4,4-difloropentyl groups; or some alkenyl groups including vinyl, 1-propenyl, 3-butenyl, 1-pentenyl, 3-pentenyl, 4-pentenyl, 1-hexenyl, 5-hexenyl, 6-heptenyl and 7-octenyl groups.
H, F and CH3 groups are desirable in practical use for W, W1 and W2.
The groups
Figure 00210001
Figure 00220001
Figure 00230001
Figure 00240001
are desirable in practical use for the ring structure
Figure 00250001
These compounds are prepared by carbon-carbon bond formation or carbon-silicon bond formation between an organometallic reagent and a compound which has an eliminatable group(s) such as a halogen atom, alkoxy, methanesulfonyl, benzenesulfonyl or p-toluenesulfonyl group. Methods of preparing these compounds are described in detail below.
First, a preferred embodiment of a method of preparing a silacyclohexane compound using a reaction between an organometallic reagent R-M and a compound
Figure 00250002
is described below. (In these formulas, M denotes MgP (P denotes a halogen atom), ZnP or Li. R denotes hydrogen, a linear-chain alkyl group with a carbon number of 1-10, a branched -chain alkyl group with a carbon number of 3-8, an alkoxyalkyl group with a carbon number of 2-7, a floroalkyl group with a carbon number of 1-10 in which one or two hydrogen atoms are are substituted by florine atom(s), or an alkenyl group with a carbon number of 2-8. Q denotes a halogen atom, alkoxy, methanesulfonyl, benzenesulfonyl or p-toluenesulfonyl group. X denotes a CN, F, Cl, CF3, CF2Cl, CHFCl, OCF3, OCHF2, OCF2Cl, OCHFCl, R or OR group. Y denotes H or F. Z denotes H or F.)
In this preparation method, when the group
Figure 00260001
(where W denotes H, F Cl or CH3), Q is a halogen atom or an alkoxy group. Particularly, if Q is a Cl or Br atom, or an OCH3 or OCH2CH3 group, then the carbon-silicon bond formation reaction proceeds easily and gives a high yield of the target product.
When the group
Figure 00260002
Figure 00270001
the carbon-carbon bond formation reaction is carried out in the presence of a copper salt. In this case, Q is a halogen atom or a methanesulfonyl, benzenesulfonyl or p-toluenesulfonyl group. It is particularly preferable if Q is Br or I, because then the target product can be obtained with a high yield.
Next, a preferred embodiment of a method of preparing a silacyclohexane compound using a reaction between an organometallic reagent
Figure 00270002
and a compound
Figure 00270003
or a reaction between the compounds
Figure 00280001
is described below. (In these formulas, M denotes MgP (P denotes a halogen atom), ZnP or Li. R denotes hydrogen, a linear-chain alkyl group with a carbon number of 1-10, a branched -chain alkyl group with a carbon number of 3-8, an alkoxyalkyl group with a carbon number of 2-7, a floroalkyl group with a carbon number of 1-10 in which one or two hydrogen atoms are substituted by florine atom(s), or an alkenyl group with a carbon number of 2-8. Q denotes a halogen atom, alkoxy, methanesulfonyl, benzenesulfonyl or p-toluenesulfonyl group. X denotes a CN, F, Cl, CF3, CF2Cl, CHFCl, OCF3, OCHF2, OCF2Cl OCHFCl, R or OR group. Y denotes H or F. Z denotes H or F. n and m are integers 0, 1 or 2 (where n+m = 2).)
In these reactions, the carbon-carbon bond formation reaction is carried out in the presence of a catalytic quantity of a copper salt. For Q, a halogen atom or a methanesulfonyl, benzensulfonyl or p-toluenesulfonyl group can be used. Particularly preferable are Br, I and the p-toluenesulfonyl group because they give a higher yield of the target product.
Next, a preferred embodiment of a method of preparing a silacyclohexane compound using a reaction between an organometallic reagent
Figure 00290001
and a compound
Figure 00290002
is described below. (In these formulas, M denotes MgP (P denotes a halogen atom), ZnP or Li. R denotes hydrogen, a linear-chain alkyl group with a carbon number of 1-10, a branched -chain alkyl group with a carbon number of 3-8, an alkoxyalkyl group with a carbon number of 2-7, a floroalkyl group with a carbon number of 1-10 in which one or two hydrogen atoms are substituted by florine atom(s), or an alkenyl group with a carbon number of 2-8. Q denotes a halogen atom, or an alkoxy, methanesulfonyl, benzenesulfonyl or p-toluenesulfonyl group. X denotes a CN, F, Cl, CF3, CF2Cl, CHFCl, OCF3, OCHF2, OCF2Cl, OCHFCl, R or OR group. Y denotes H or F. Z denotes H or F.)
In this preparation method, when the group
Figure 00300001
(where W denotes H, F Cl or CH3), Q is a halogen atom or an alkoxy group. It is particularly preferable if Q is a Cl or Br atom, or an OCH3 or OCH2CH3 group, because then the carbon -silicon bond formation reaction proceeds easily and gives a high yield of the target product.
Also, when the group
Figure 00300002
Figure 00310001
the carbon-carbon bond formation reaction is carried out in the presence of a copper salt. In this case, Q is a halogen atom or a methanesulfonyl, benzenesulfonyl or p-toluenesulfonyl group. It is particularly preferable if Q is Br , I or the p-toluenesulfonyl group, because then the target product can be obtained with a high yield.
Next, a preferred embodiment of a method of preparing a silacyclohexane compound using a reaction between an organometallic reagent
Figure 00310002
and a compound
Figure 00310003
is described below. {In these formulas, M' denotes MgP (P denotes a halogen atom), ZnP or B(OY') (Y' denotes H or an alkyl group). R denotes hydrogen, a linear-chain alkyl group with a carbon number of 1-10, a branched-chain alkyl group with a carbon number of 3-8, an alkoxyalkyl group with a carbon number of 2-7, a fluoroalkyl group with a carbon number of 1-10 in which one or two hydrogen atoms are substituted by florine atom(s), or an alkenyl group with a carbon number of 2-8. Q denotes a halogen atom, or an alkoxy, methanesulfonyl or p-toluenesulfonyl group. X denotes a CN, F, Cl, CF3, CF2 Cl, CHFCl, OCF3, OCHF2, OCF2Cl, OCHFCl R or OR group. Y denotes H or F. Z denotes H or F.}
This reaction is carried out in the presence of a transition metal catalyst. Palladium compounds and nickel compounds are particularly preferable for the catalyst. Q is a halogen atom or a methanesulfonyl, benzenesulfonyl or p-toluenesulfonyl group. Particularly preferable are Cl, Br and I because they give a higher yield of the target product.
The compound produced here may be a mixture of trans isomers and cis isomers in terms of the conformation of the silacyclohexane ring. If this is the case, then a conventional purification means such as chromatography and recrystallization is employed to separate and purify the trans isomers to obtain the silacyclohexane compound of this invention represented by the general formula (I).
The silacyclohexane compound of this invention can be mixed with known compounds to obtain a liquid crystal composition. The compound used for mixing to obtain the liquid crystal compound can be chosen from among the known compounds shown below:
Figure 00330001
In the above formulas, (M) and (N) denote one of the following:
  • 1) A trans-1,4-cyclohexylene group which has no substitution or which has one or more substitutional groups such as F, Cl, Br, CN or alkyl groups,
  • 2) A ring comprising a cyclohexane ring in which O or S is substituted for one or nonadjacent two CH2 groups,
  • 3) A 1,4-cyclohexenylene group,
  • 4) A 1,4-phenylene group which has no substitution or which has one or two substitutional groups such as F, Cl, CH3 or CN groups, or
  • 5) A ring comprising a 1,4-phenylene group in which an N atom is substituted for one or two CH groups.
    • A1 and A2 denote -CH2CH2-, -CH=CH-, -C≡C-, -CO2-, -OCO -, -CH2O-, -OCH2- or a single bond.
    • ℓ, m = 0, 1 or 2 (where ℓ + m = 1, 2 or 3, and n = 0, 1 or 2)
    • R denotes hydrogen, a linear-chain alkyl group with a carbon number of 1-10, a branched-chain alkyl group with a carbon number of 3-8, an alkoxyalkyl group with a carbon number of 2-7, a floroalkyl group with a carbon number of 1 -10 in which one or two hydrogen atoms are substituted by florine atom(s), or an alkenyl group with a carbon number of 2-8.
    • X, Y and Z are the same as defined for the general formula (I).
    In the above description, if ℓ or n = 2, then (M) can contain heterogeneous rings, and if m = 2, then (N) can contain heterogeneous rings.
    The ratio of one or more types of the silacyclohexane compound of this invention contained in the liquid crystal composition is preferably 1-50 wt%, more preferably 5-30 wt%. The liquid crystal composition can also contain a polygenetic dye(s) to generate the colored guest-host system and additives to change the dielectric anisotropy, viscosity and the orientation of the nematic phase.
    The liquid crystal composition thus formed can be used to manufacture various liquid crystal display elements in conventional methods. That is, the liquid crystal composition containing the silacyclohexane compound of this invention is sealed between transparent plates which have electrodes of desired shapes and thus used as liquid crystal display elements. These elements can have various undercoatings, overcoatings for orientation control, a polarizer plate(s), a filter(s) and a reflector layer(s), as necessary. They can be made into a laminated cell or combined with other display elements. Semiconductor substrates and light sources can also be used to make various types of displays.
    For the driving method of the liquid crystal display element, prior-art methods in the industry of liquid crystal display elements, such as the dynamic scattering (DSM) method, the twisted nematic (TN) method, the guest-host (GH) method, the super twisted nematic (STN) method and the polymer dispersion liquid crystal (PDLC) method can be adopted.
    EXAMPLES
    The details of this invention are described below by referring to specific examples.
    [Example 1] (Preparation of trans-4-(2-(trans-4-(3, 4-difluorophenyl) cyclohexyl) eth- yl)-1-n-propyl-1-silacyclohexane)
    A mixed solution of 3.7 g (10 mmol) of 1-chloro-4-(2 -(trans-4-(3,4-difluorophenyl)cyclohexyl)ethyl)-1-silacyclohexane and 30 ml of tetrahydrofuran (hereafter abbreviated as "THF") was prepared, and a 5 ml THF solution of 2.5 M n-propylmagnesium chloride (12.5 mmol) was dripped into this solution. The silacyclohexane rings of the target product thus obtained were a mixture of trans isomers and cis isomers. Following a conventional after treatment, they were separated by means of chromatography to obtain 2.9 g of the trans isomers of the target product (yield 80%). The results of its analysis are shown below.
  • IR (liquid film) νmax: 2922, 2850, 2100, 1606, 1518, 1288, 887 and 815 cm-1.
  • C-N transition temperature: 11.2°C, N-I transition temperature: 63.5°C.
    • As shown above, it was confirmed that this product exhibited the nematic phase in the temperature range of 11.2°C-63.5°C, and that the temperature range of the nematic phase was extended significantly on the low temperature end compared with the existing trans-4-(2-(trans-4-(3,4-difluorophenyl)cyclohexyl) ethyl)-1-n-propyl-1-cyclohexane (C-N transition temperature 36.0°C).
    [Example 2] (Preparation of trans-1-n-propyl-4-(2-(trans-4-(3,4,5-trifluorophenyl)cyclohexyl)ethyl)-1-silacyclohexane)
    The preparation was conducted in the same manner as in Example 1, except that 3.8 g (10 mmol) of 1-chloro-4-(2-(trans-4-(3,4,5-trifluorophenyl)cyclohexyl)ethyl)-1-silacyclohexane was used instead of 3.7 g (10 mmol) of 1-chloro-4-(2-(trans -4-(3,4-difluorophenyl)cyclohexyl)ethyl)-1-silacyclohexane.
    [Example 3] (Preparation of trans-1-n-propyl-4-(2-(trans-4-(p-trifluoro -methoxyphenyl)cyclohexyl)ethyl)-1-fluoro-1-silacyclohexane)
    The preparation was conducted in the same manner as in Example 1, except that 4.1 g (10 mmol) of 1,1-difluoro-4 -(2-(trans-4-(p-trifluoromethoxyphenyl)cyclohexyl)ethyl-1-silacyclohexane was used instead of 3.7 g (10 mmol) of 1-chloro -4-(2-(trans-4-(3,4-difluorophenyl)cyclohexyl)ethyl)-1-silacyclohexane.
    [Example 4] (Preparation of trans-1-n-propyl-4-(2-(trans-4-(p-trifluoro -methoxyphenyl)cyclohexyl)ethyl)-1-silacyclohexane)
    The preparation was conducted in the same manner as in Example 1, except that 3.9 g(10 mmol) of 1-chloro-4-(2-(trans -4-(p-trifluoromethoxyphenyl)cyclohexyl)ethyl)-1-silacyclohexane was used instead of 3.7 g (10 mmol) of 1-chloro-4-(2-(trans -4-(3,4-difluorophenyl)cyclohexyl)ethyl)-1-silacyclohexane.
  • IR (liquid film) νmax: 2922, 2850, 2100, 1510, 1261, 1223, 1167 and 842 cm-1.
  • C-N transition temperature: 31.5°C, N-I transition temperature: 84.9°C.
    • [Example 5] (Preparation of trans-4-(2-(trans-4-(4-chloro-3-fluorophenyl) cyclohexyl) ethyl)-1-n-propyl-1-silacyclohexane)
    The preparation was conducted in the same manner as in Example 1, except that 3.7 g(10 mmol) of 1-chloro-4-(2-(trans -4-(4-chloro-3-fluorophenyl)cyclohexyl)ethyl-1-silacyclohexane was used instead of 3.7 g (10 mmol) of 1-chloro-4-(2-(trans -4-(3,4-difluorophenyl)cyclohexyl)ethyl)-1-silacyclohexane.
    [Example 6] (Preparation of trans-4-(2-(trans-4-(p-fluorophenyl)cyclohexyl) ethyl)-1-n-pentyl-1-silacyclohexane)
    A 15 ml THF solution of 2.5 M n-pentylzinc chloride (37.5 mmol) (prepared from a corresponding Grignard's reagent and zinc chloride) was dripped into a mixed solution of 7.0 g (21 mmol) of 1-chloro-4-(2-(trans-4-(p-fluorophenyl)cyclohexyl) ethyl)-1-silacyclohexane and 60 ml of THF. The silacyclohexane rings of the target productthus obtained were a mixture of trans isomers and cis isomers. Following a conventional after treatment, they were separated by means of chromatography to obtain 5.9 g of the trans isomers of the target product (yield 75%). The results of its analysis are shown below.
  • IR (KBr) νmax: 2916, 2848, 2102, 1508, 1221, 1159, 885 and 833cm-1
  • C-N transition temperature: 44.3°C, N-I transition temperature: 83.8°C
    • [Example 7] (Preparation of trans-4-(2-(trans-4-(p-fluorophenyl)cyclohexyl) ethyl)-1-ethyl-1-silacyclohexane)
    The preparation was conducted in the same manner as in Example 6, except that ethylzinc chloride was used instead of n-pentylzinc chloride.
  • IR (KBr) νmax: 2914, 2850, 2110, 1508, 1219, 825, 814 and 766 cm-1
  • C-N transition temperature: 62.5°C, N-I transition temperature: 77.9°C
    • [Example 8] (Preparation of trans-4-(2-(trans-4-(3,4-difluorophenyl)cyclohexyl) ethyl)-1-ethyl-1-silacyclohexane)
    The preparation was conducted in the same manner as in Example 6, except that 7.5 g (21 mmol) of 1-chloro-4-(2-(trans-4-(3,4-difluorophenyl)cyclohexyl)ethyl)-1-silacyclohexane and ethylzinc chloride were used instead of 7.0 g (21 mmol) of 1-chloro-4-(2-(trans-4-(p-fluorophenyl)cyclohexyl)ethyl) -1-silacyclohexane and n-pentylzinc chloride.
  • IR (liquid film) νmax: 2920, 2850, 2098, 1518, 1290, 1286, 887, 816 and 769 cm-1
  • C-N transition temperature: 33.4°C, N-I transition temperature: 48.4°C
    • [Example 9] (Preparation of trans-4-(2-(trans-4-(p-chlorophenyl) cyclohexyl) ethyl)-1-n-pentyl-1-silacyclohexane)
    The preparation was conducted in the same manner as in Example 6, except that 7.5 g (21 mmol) of 1-chloro-4-(2-(trans-4-(p-chlorophenyl)cyclohexyl)ethyl)-1-silacyclohexane was used instead of 7.0 g (21 mmol) of 1-chloro-4-(2-(trans -4 (p-fluorophenyl)cyclohexyl)ethyl)-1-silacyclohexane.
  • IR (KBr) νmax: 2916, 2846, 2096, 1493, 1092, 889 and 818 cm-1
  • C-N transition temperature: 35.9°C, N-I transition temperature: 99.5°C
    • [Example 10] (Preparation of trans-4-(2-(trans-4-(p-cyanophenyl)cyclohexyl) ethyl)-1-n-pentyl-1-silacyclohexane)
    The preparation was conducted in the same manner as in Example 6, except that 7.3 g (21 mmol) of 1-chloro-4-(2-(trans-4-(p-cyanophenyl)cyclohexyl)ethyl)-1-silacyclohexane was used instead of 7.0 g (21 mmol) of 1-chloro-4-(2-(trans -4-(p-fluorophenyl)cyclohexyl)ethyl)-1-silacyclohexane.
    [Example 11] (Preparation of trans-4-(2-(trans-4-(2,3-difluoro-4-ethoxyphenyl) cyclohexyl)ethyl)-1-n-pentyl-1-silacyclohexane)
    The preparation was conducted in the same manner as in Example 6, except that 8.4 g (21 mmol) of 1-chloro-4-(2-(trans-4-(2,3-difluoro-4-ethoxyphenyl)cyclohexyl)ethyl)-1-silacyclohexane was used instead of 7.0 g (21 mmol) of 1-chloro -4-(2-(trans-4-(p-fluorophenyl)cyclohexyl)ethyl)-1-silacyclohexane.
    [Example 12] (Preparation of trans-4-(2-(trans-4-(3,5-difluoro-4-difluoro -methoxyphenyl)cyclohexyl)ethyl)-1-n-pentyl-1-silacyclohexane)
    The preparation was conducted in the same manner as in Example 6, except that 8.9 g (21 mmol) of 1-chloro-4-(2-(trans-4-(3,5-difluoro-4-difluoromethoxyphenyl)cyclohexyl)ethyl) -1-silacyclohexane was used instead of 7.0 g (21 mmol) of 1 -chloro-4-(2-(trans-4-(p-fluorophenyl)cyclohexyl)ethyl)-1-silacyclohexane.
    [Example 13] (Preparation of trans-4-(2-(trans-4-(p-trifluoromethylphenyl) cyclohexyl) ethyl)-1-n-propyl-1-silacyclohexane)
    The preparation was conducted in the same manner as in Example 6, except that 8.2 g (21 mmol) of 1-chloro-4-(2-(trans-4-(p-trifluoromethylphenyl)cyclohexyl)ethyl)-1-silacyclohexane and n-propylzinc chloride were used instead of 7.0 g (21 mmol) of 1-chloro-4-(2-(trans-4-(p-fluorophenyl)cyclohexyl)ethyl) -1-silacyclohexane and n-pentylzinc chloride.
    [Example 14] (Preparation of trans-4-(2-(trans-4-(3, 5-difluoro-4-chlorophenyl) cyclohexyl) ethyl)-1-n-pentyl-1-silacyclohexane)
    The preparation was conducted in the same manner as in Example 6, except that 8.2 g (21 mmol) of 1-chloro-4-(2-(trans-4-(3,5-difluoro-4-chlorophenyl)cyclohexyl)ethyl)-1-silacyclohexane was used instead of 7.0 g (21 mmol) of 1-chloro -4-(2-(trans-4-(p-fluorophenyl)cyclohexyl)ethyl)-1-silacyclohexane.
    [Example 15] (Preparation of trans-4-(2-(trans-4-(3,4-difluorophenyl) cyclohexyl)ethyl)-1-(4-pentenyl)-1-silacyclohexane)
    The preparation was conducted in the same manner as in Example 6, except that 7.5 g (21 mmol) of 1-chloro-4-(2-(trans-4-(3,4-difluorophenyl)cyclohexyl)ethyl)-1-silacyclohexane and 4-pentenylzinc chloride were used instead of 7.0 g (21 mmol) of 1-chloro-4-(2-(trans-4-(p-fluorophenyl)cyclohexyl) ethyl)-1-silacyclohexane and n-pentylzinc chloride.
    [Example 16] (Preparation of trans-4-(2-(trans-4-(3,4-difluorophenyl) cyclohexyl) ethyl)-1-(3-methoxypropyl)-1-silacyclohexane)
    The preparation was conducted in the same manner as in Example 6, except that 7.5 g (21 mmol) of 1-chloro-4-(2-(trans-4-(3,4-difluorophenyl)cyclohexyl)ethyl)-1-silacyclohexane and 3-methoxypropylzinc chloride were used instead of 7.0 g (21 mmol) of 1-chloro-4-(2-(trans-4-(p-fluorophenyl)cyclohexyl) ethyl)-1-silacyclohexane and n-pentylzinc chloride.
    [Example 17] (Preparation of trans-4-(2-(trans-4-(3,4-difluorophenyl) cyclohexyl) ethyl)-1-(3-methylbutyl)-1-silacyclohexane)
    The preparation was conducted in the same manner as in Example 6, except that 7.5 g (21 mmol) of 1-chloro-4-(2-(trans-4-(3,4-difluorophenyl)cyclohexyl)ethyl)-1-silacyclohexane and 3-methylbutylzinc chloride were used instead of 7.0 g (21 mmol) of 1-chloro-4-(2-(trans-4-(p-fluorophenyl)cyclohexyl) ethyl)-1-silacyclohexane and n-pentylzinc chloride.
    [Example 18] (Preparation of trans-1-(2-(trans-4-n-butylcyclohexyl)ethyl) -4-(3,4-difluorophenyl)-1-silacyclohexane)
    A 55 ml THF solution of 2.0 M 2-(trans-4-n-butylcyclohexyl) ethylmagnesium bromide (110 mmol) was dripped into a mixed solution of 24.6 g (100 mmol) of 1-chloro-4-(3, 4-difluorophenyl) -1-silacyclohexane and 250 ml of THF. The silacyclohexane rings of the target product thus obtained were a mixture of trans isomers and cis isomers. Following a conventional after treatment, they were separated by means of chromatography to obtain 28.3 g of the trans isomers of the target product (yield 75%). The results of its analysis are shown below.
  • IR (liquid film) νmax: 2918, 2850, 2102, 1608, 1518, 1213, 889 and 812 cm-1.
  • C-N transition temperature: 6.2°C, N-I transition temperature: 37.7°C.
    • As shown above, it was confirmed that this product exhibited the nematic phase in the temperature range of 6.2°C-37.7°C, and that the temperature range of the nematic phase was extended significantly on the low temperature end compared with the existing trans-1-(2-(trans-4-n-butylcyclohexyl)ethyl)-4-(3, 4-difluorophenyl)-1-cyclohexane (C-N transition temperature 32.0°C).
    [Example 19] (Preparation of trans-1-(2-(trans-4-ethylcyclohexyl)ethyl) -4-p-fluorophenyl-1-silacyclohexane)
    The preparation was conducted in the same manner as in Example 18, except that 22.8 g (100 mmol) of 1-chloro-4-(p-fluorophenyl)-1-silacyclohexane and 2-(trans-4-ethylcyclohexyl) ethylmagnesium bromide were used instead of 24.6 g (100 mmol) of 1-chloro-4-(3,4-difluorophenyl)-1-silacyclohexane and 2-(trans-4-n-butylcyclohexyl)ethylmagnesium bromide.
  • IR (liquid film) νmax: 2916, 2850, 2100, 1510, 1228, 985, 887, 812 and 787 cm-1.
  • C-I transition temperature: 35.3°C.
    • [Example 20] (Preparation of trans-1-(2-(trans-4-ethylcyclohexyl)ethyl) -4-(3,4-difluorophenyl)-1-silacyclohexane)
    The preparation was conducted in the same manner as in Example 18, except that 2-(trans-4-ethylcyclohexyl) ethylmagnesium bromide was used instead of 2-(trans-4-n-butylcyclohexyl) ethylmagnesium bromide.
  • IR (liquid film) νmax: 2916, 2850, 2100, 1608, 1518, 1286, 1213, 1115, 987, 889, 812 and 769 cm-1.
  • C-N transition temperature: 13.3°C, N-I transition temperature: 19.5°C.
    • [Example 21] (Preparation of trans-1-(2-(trans-4-n-propylcyclohexyl)ethyl) -4-(3,4-difluorophenyl)-1-silacyclohexane)
    The preparation was conducted in the same manner as in Example 18, except that 2-(trans-4-n-propylcyclohexyl)ethylmagnesium bromide was used instead of 2-(trans-4-n-butylcyclohexyl) ethylmagnesium bromide.
  • IR (liquid film) νmax: 2916, 2848, 2102, 1608, 1518, 1284, 1213, 889, 812 and 769 cm-1.
  • C-N transition temperature: 20.1°C, N-I transition temperature: 34.0°C.
    • [Example 22] (Preparation of trans-4-(2-(trans-4-(p-fluorophenyl)cyclohexyl) ethyl)-1-n-propyl-1-silacyclohexane)
    A 30 ml THF solution of 2.0 M (trans-4-n-propyl-4-silacyclohexyl)methylmagnesium bromide (60 mmol) was dripped into a mixed solution of 18.1 g (50 mmol) of (trans-4-(p-fluorophenyl) cyclohexyl)methyl p-toluenesulfonate and 150 ml of THF. The silacyclohexane rings of the target product thus obtained were a mixture of trans isomers and cis isomers. Following a conventional after treatment, they were separated by means of chromatography to obtain 12.4 g of the trans isomers of the target product (yield 72%). The results of its analysis are shown below.
  • IR (KBr) νmax: 2916, 2848, 2106, 1508, 1221, 885 and 883 cm-1
  • C-N transition temperature: 43.9°C, N-I transition temperature: 93.8°C
    • [Example 23] (Preparation of trans-1-n-pentyl-4-(2-(trans-4-(p-methoxyphenyl) cyclohexyl) ethyl)-1-silacyclohexane)
    The preparation was conducted in the same manner as in Example 22, except that 18.7 g (50 mmol) of (trans-4-(p-methoxyphenyl)cyclohexyl)methyl p-toluenesulfonate and (trans -4-n-pentyl-4-silacyclohexyl)methylmagnesium bromide were used instead of 18.1 g (50 mmol) of (trans-4-(p-fluorophenyl) cyclohexyl)methyl p-toluenesulfonate and (trans-4-n-propyl-4-silacyclohexyl)methylmagnesium bromide.
    [Example 24] (Preparation of trans-4-(2-(trans-4-(3-fluoro-4-trifluoro methoxyphenyl)cyclohexyl)ethyl)-1-n-pentyl-1-silacyclohexane)
    The preparation was conducted in the same manner as in Example 22, except that 22.9 g (50 mmol) of (trans-4-(3-fluoro-4-trifluoromethoxyphenyl)cyclohexyl)methyl p-toluenesulfonate and (trans-4-n-pentyl-4-silacyclohexyl)methylmagnesium bromide were used instead of 18.1 g (50 mmol) of (trans-4-(p-fluorophenyl) cyclohexyl)methyl p-toluenesulfonate and (trans-4-n-propyl-4-silacyclohexyl)methylmagnesium bromide.
    [Example 25] (Preparation of trans-4-(p-fluorophenyl)-1-(2-(trans-4-n-pentyl -4-silacyclohexyl)ethyl)-1-silacyclohexane)
    The preparation was conducted in the same manner as in Example 22, except that 18.9 g (50 mmol) of (trans-4-(p-fluorophenyl)-1-silacyclohexyl)methyl p-toluenesulfonate and (trans-4-n-pentyl-4-silacyclohexyl)methylmagnesium bromide were used instead of 18.1 g (50 mmol) of (trans-4-(p-fluorophenyl) cyclohexyl)methyl p-toluenesulfonate and (trans-4-n-propyl-4-silacyclohexyl)methylmagnesium bromide.
    [Example 26] (Preparation of trans-1-(2-(trans-4-(3, 4-difluorophenyl) cyclohexyl) ethyl)-4-n-pentyl-1-silacyclohexane)
    A 35 ml THF solution of 1.5 M 2-(trans-4-(3, 4-difluorophenyl) cyclohexyl)ethyl lithium (52.5 mmol) was dripped into a mixed solution of 10.0 g (50 mmol) of 1-methoxy-4-n-pentyl-1-silacyclohexane and 100 ml of THF. The silacyclohexane rings of the target product thus obtained were a mixture of trans isomers and cis isomers. Following a conventional after treatment, they were separated by means of chromatography to obtain 12.9 g of the trans isomers of the target product (yield 69%). The results of its analysis are shown below.
  • IR (liquid film) νmax: 2920, 2850, 2098, 1608, 1518, 1288, 1286, 887, 862 and 816 cm-1.
  • C-N transition temperature: 14.7°C, N-I transition temperature: 28.9°C.
    • As shown above, it was confirmed that this product exhibited the nematic phase in the temperature range of 14.7°C-28.9°C, and that the temperature range of the nematic phase was extended significantly on the low temperature end compared with the existing trans-1-(2-(trans-4 (3,4-difluorophenyl)cyclohexyl) ethyl)-4-n-pentyl-1-cyclohexane (C-N transition temperature 38.0°C).
    [Example 27] (Preparation of trans-4-(2-(trans-4-(3,4-difluorophenyl)cyclohexyl) ethyl)-1-n-pentyl-1-silacyclohexane)
    The preparation was conducted in the same manner as in Example 26, except that 17.4 g (50 mmol) of trans-4-(2-(trans -4-(3,4-difluorophenyl)cyclohexyl)ethyl)-1-methoxy-1-silacyclohexane and n-pentyl lithium were used instead of 10.0 g (50 mmol) of 1-methoxy-4-n-pentyl-1-silacyclohexane and 2-(trans-4-(3, 4-difluorophenyl)cyclohexyl)ethyl lithium.
  • IR (liquid film) νmax: 2920, 2850, 2098, 1608, 1518, 1290, 1286 and 816 cm-1
  • C-N transition temperature: 8.0°C, N-I transition temperature: 66.1°C
    • [Example 28] (Preparation of trans-1-(2-(trans-4-n-butylcyclohexyl)ethyl) -4-n-(p-fluorophenyl)-1-silacyclohexane)
    The preparation was conducted in the same manner as in Example 26, except that 11.2 g (50 mmol) of trans-4-(p-fluorophenyl) -1-methoxy-1-silacyclohexane and 2-(trans-4-n-butylcyclohexyl) ethyl lithium were used instead of 10.0 g (50 mmol) of 1-methoxy -4-n-pentyl-1-silacyclohexane and 2-(trans-4-(3,4-difluorophenyl) cyclohexyl)ethyl lithium.
  • IR (liquid film) νmax: 2918, 2850, 2102, 1605, 1510, 1228, 985, 887, 881 and 812 cm-1
  • S-N transition temperature: 20.7°C, C-N transition temperature: 22.0°C, N-I transition temperature: 74.6°C
    • [Example 29]
    (Preparation of trans-4-(p-fluorophenyl)-1-(2-(trans-4-n-pentylcyclohexyl) ethyl)-1-silacyclohexane)
    The preparation was conducted in the same manner as in Example 26, except that 11.2 g (50 mmol) of trans-4-(p-fluorophenyl) -1-methoxy-1-silacyclohexane and 2-(trans-4-n-pentylcyclohexyl) ethyl lithium were used instead of 10.0 g (50 mmol) of 1-methoxy -4-n-pentyl-1-silacyclohexane and 2-(trans-4-(3,4-difluorophenyl) cyclohexyl)ethyl lithium.
  • IR (KBr) νmax: 2918, 2848, 2102, 1510, 1232, 887, 881 and 816 cm-1
  • C-S transition temperature: 25.4°C, S-N transition temperature: 32.5°C, N-I transition temperature: 82.0°C
    • [Example 30] (Preparation of 4-(p-fluorophenyl)-1-(2-(trans-4-n-propylcyclohexyl) ethyl)-1-silacyclohexane)
    A 25 ml THF solution of 1.0 M (4-(p-fluorophenyl)-1-silacyclohexyl methylmagnesium chloride (25 mmol) was dripped into a mixed solution of 4.5 g (19.9 mmol) of trans-1-iodomethyl -4-n-propylcyclohexane, 10 mg of copper iodide (I), 50 mg of triethyl phosphite and 50 ml of THF. The silacyclohexane rings of the target product thus obtained were a mixture of trans isomers and cis isomers. Following a conventional after treatment, they were separated by means of chromatography to obtain 5. 7 g of the trans isomers of the target product (yield 82.9%). The results of its analysis are shownbelow.
  • IR (KBr) νmax: 2908, 2848, 2096, 1510, 1223, 985, 887, 831, 814 and 735 cm-1
  • C-N transition temperature: 49.1°C, N-I transition temperature: 69.2°C
    • [Example 31] (Preparation of 4-(3,4-difluorophenyl)-1-(2-(trans-4-n-pentylcyclohexyl)ethyl)-1-silacyclohexane)
    The preparation was conducted in the same manner as in Example 30, except that 5.9 g (19.9 mmol) of trans-1-iodomethyl -4-n-pentylcyclohexane and (4-(3,4-difluorophenyl)-1-silacyclohexyl) methylmagnesium chloride were used instead of 4.5 g (19.9 mmol) of trans-1-iodomethyl-4-n-propylcyclohexane and (4-(p-fluorophenyl) -1-silacyclohexyl)methylmagnesium chloride.
  • IR (KBr) νmax: 2920, 2848, 2106, 1518, 1215, 1115, 987, 889, 812 and 768 cm-1
  • C-N transition temperature: 33.3°C, N-I transition temperature: 60.0°C
    • [Example 32] (Preparation of trans-4-isobutyl-1-(2-(trans-4-(p-fluorophenyl) cyclohexyl)ethyl)-1-silacyclohexane)
    The preparation was conducted in the same manner as in Example 30, except that 6.3 g (19.9 mmol) of trans-1-iodomethyl -4-(p-fluorophenyl)cyclohexane and (4-n-isobutyl-1-silacyclohexyl) methylmagnesium chloride were used instead of 4.5 g (19.9 mmol) of trans-1-iodomethyl-4-n-propylcyclohexane and (4-(p-fluorophenyl) -1-silacyclohexyl)methylmagnesium chloride.
    [Example 33] (Preparation of 1-(3,4-difluorophenyl)-4-(2-(trans-4-n-pentylcyclohexyl) ethyl)-1-silacyclohexane)
    A 15 ml THF solution of 1.0 M 3,4-difluorophenylmagnesium bromide (15 mmol) was dripped into a mixed solution of 2.5 g (7.9 mmol) of 1-chloro-4-(2-(trans-4-n-pentylcyclohexyl) ethyl)-1-silacyclohexane and 50 ml of THF.
    The silacyclohexane rings of the target product thus obtained were a mixture of trans isomers and cis isomers. Following a conventional after treatment, they were separated by means of chromatography to obtain 2.0 g of the trans isomers of the target product (yield64%).
    [Example 34] (Preparation of trans-4-(2-(trans-4-(p-n-propylphenyl)cyclohexyl) ethyl)-1-n-propyl-1-silacyclohexane)
    The preparation was conducted in the same manner as in Example 33, except that 2.6 g (7.9 mmol) of 1-bromo-4-(2 -(trans-4-n-propyl-4-silacyclohexyl)ethyl)cyclohexane and p-n-propylphenylmagnesium bromide were used instead of 2.5 g (7.9 mmol) of 1-chloro-4-(2-(trans-4-n-pentylcyclohexyl) ethyl)-1-silacyclohexane and 3,4-difluorophenylmagnesium bromide.
    [Example 35] (Preparation of trans-1-(3,4-difluorophenyl)-1-methyl-4-(2 -(trans-4-n-pentylcyclohexyl) ethyl)-1-silacyclohexane)
    The preparation was conducted in the same manner as in Example 33, except that 2.6 g (7.9 mmol) of 1-chloro-1-methyl -4-(2-(trans-4-n-pentylsilacyclohexyl)ethyl)-1-silacyclohexane was used instead of 2.5 g (7.9 mmol) of 1-chloro-4-(2-(trans -4-n-pentylcyclohexyl)ethyl)-1-silacyclohexane.
    [Example 36] (Preparation of trans-4-(2-(trans-4-(p-trifluoromethoxyphenyl) cyclohexyl)ethyl)-1-(4-fluorobutyl)-1-silacyclohexane)
    The preparation was conducted in the same manner as in Example 33, except that 2.9 g (7.9 mmol) of 1-bromo-4-(2 -(trans-4-(4-fluorobutyl)-4-silacyclohexyl)ethyl)cyclohexane was used instead of 2.5 g (7.9 mmol) of 1-chloro-4-(2-(trans -4-n-pentylcyclohexyl)ethyl)-1-silacyclohexane and p-trifluoromethoxymagnesium bromide was used instead of 3,4-difluorophenylmagnesium bromide.
    [Example 37] (Preparation of trans-4-(2-(trans-4-(3,4-difluorophenyl)cyclohexyl) ethyl)-1-(4-fluoropentyl)-1-silacyclohexane)
    The preparation was conducted in the same manner as in Example 33, except that 3.0 g (7.9 mmol) of 1-bromo-4-(2 -(trans-4-(4-fluoropentyl)-4-silacyclohexyl)ethyl)cyclohexane was used instead of 2.5 g (7.9 mmol) of 1-chloro-4-(2-(trans -4-n-pentylcyclohexyl)ethyl)-1-silacyclohexane.
    The compounds of this invention obtained in the examples described above were added to existing liquid crystal compositions to prepare liquid crystal compositions of this invention. The transition temperature(s) and the threshold voltage at 25°C were measured for the obtained liquid crystal compositions.
    [Example 38]
    Mixture A comprising 43 mole% of trans-4-(2-(trans-4 -(3,4-difluorophenyl)cyclohexyl)ethyl)-1-ethyl-1-silacyclohexane, 17 mole% of trans-4-(2-(trans-4-(3,4-difluorophenyl)cyclohexyl) ethyl)-1-n-propyl-1-silacyclohexane and 40 mole% of trans-4 -(2-(trans-4-(3,4-difluorophenyl)cyclohexyl)ethyl)-1-pentyl -1-silacyclohexane exhibited the following characteristics:
  • C-N transition temperature: -10.7°C
  • N-I transition temperature: 93.8°C
  • Threshold voltage (5 micrometer-cell, 32 Hz): 2.5 V
    • A mixture comprising 85 mole% of this mixture A and 15 mole% of trans-4-(2-(trans-4-(3,4-difluorophenyl)cyclohexyl) ethyl)-1-n-pentyl-1-silacyclohexane obtained in Example 27 exhibited the following characteristics:
  • C-N transition temperature: -16.5°C
  • N-I transition temperature: 89.6°C
  • Threshold voltage (5 micrometer-cell, 32 Hz): 2.35 V
    • The liquid crystal compounds of this invention which have Si as a ring composing element have the following advantages over liquid crystal compounds which have a conventional CECP structure comprising similar hydrocarbon rings:
  • (1) Since the nematic phase is extended on the low temperature end, the viscosity in a low temperature range decreases, resulting in the improved response time in the low temperature range.
  • (2) Mutual solubility in a low temperature range improves.
    • Also, liquid crystal compounds whose X in the general formula (I) is neither R nor OR have, in addition to the advantages mentioned above, the effect of lowering the threshold voltage because of a greater dielectric anisotropy.
    The liquid crystal compounds of this invention, depending on the selection of their substitutional groups, can be widely used as the base material which comprises the major component of the liquid crystal phase, in a manner similar to how the conventional liquid crystal compounds with a CECP structure of similar hydrocarbon rings are used. The liquid crystal compound whose substitutional group X in the general formula (I) is R or OR has negative or near-zero dielectric anisotropy, and therefore it should preferably be used for the liquid crystal phase for display based on the dynamic scattering (DS), guest -host (GH) or deformation of aligned phase (DAP mode). The compounds in which X is other than these should preferably be used for manufacturing the liquid crystal phase with a large positive dielectric anisotropy which is used in display elements based on the twisted nematic cell or the cholesteric-nematic phase transition.

    Claims (8)

    1. A silacyclohexane compound represented by the following general formula (1).
      Figure 00550001
      wherein
      R denotes hydrogen, a linear-chain alkyl group with a carbon number of 1-10, a branched-chain alkyl group with a carbon number of 3-8, an alkoxyalkyl group with a carbon number of 2-7, a fluoroalkyl group with a carbon number of 1-10 in which one or two hydrogen atoms are substituted by fluorine atom(s), or an alkenyl group with a carbon number of 2-8, of the groups
      Figure 00550002
      at least one is a trans-1-sila-1,4-cyclohexylene or trans-4-sila-1,4-cyclohexylene group whose silicon at position 1 or position 4 has a substitutional group(s) of H, F, Cl or CH3, and the other denotes a trans-1,4-cyclohexylene group,
      X denotes a CN, F, Cl, CF3, CF2Cl, CHFCl, OCF3, OCHF2, OCF2Cl, OCHFCl, R or OR group (wherein R is the same as defined in the general formula (I)),
      Y denotes H or F and
      Z denotes H or F.
    2. A method for preparing the silacyclohexane compound as defined in claim 1 characterized by reacting an organometallic reagent R-M with a compound of formula
      Figure 00560001
      wherein
      M denotes MgP (P denotes a halogen atom), ZnP or Li,
      R denotes hydrogen, a linear-chain alkyl group with a carbon number of 1-10, a branched-chain alkyl group with a carbon number of 3-8, an alkoxyalkyl group with a carbon number of 2-7, a fluoroalkyl group with a carbon number of 1-10 in which one or two hydrogen atoms are substituted by fluorine atom(s), or an alkenyl group with a carbon number of 2-8,
      Q denotes a halogen atom, or an alkoxy, methanesulfonyl, benzenesulfonyl or p-toluenesulfonyl group.
      X denotes a CN, F, Cl, CF3, CF2Cl, CHFCl, OCF3, OCHF2, OCF2Cl, OCHFCl, R or OR group (wherein R is as defined above),
      Y denotes H or F,
      Z denotes H or F.
    3. A method for preparing the silacyclohexane compound as defined in claim 1 characterized by reacting an organometallic reagent of formula
      Figure 00560002
      with a compound of formula
      Figure 00560003
      wherein
      M denotes MgP (P denotes a halogen atom), ZnP or Li,
      R denotes hydrogen, a linear-chain alkyl group with a carbon number of 1-10, a branched-chain alkyl group with a carbon number of 3-8, an alkoxyalkyl group with a carbon number of 2-7, a fluoroalkyl group with a carbon number of 1-10 in which one or two hydrogen atoms are substituted by fluorine atom(s), or an alkenyl group with a carbon number of 2-8,
      Q denotes a halogen atom, an alkoxy, methanesulfonyl, benzenesulfonyl or p-toluenesulfonyl group,
      X denotes a CN, F, Cl, CF3, CF2 Cl, CHFCl, OCF3, OCHF2, OCF2Cl, OCHFCl, R or OR group (wherein R is as defined above),
      Y denotes H or F,
      Z denotes H or F and
      n and m are integers of from 0, 1 or 2 (where n+m = 2).
    4. A method for preparing the silacyclohexane compound as defined in claim 1 characterized by reacting an organometallic reagent of formula
      Figure 00570001
      with a compound of formula
      Figure 00570002
      wherein
      M denotes MgP (P denotes a halogen atom), ZnP or Li,
      R denotes hydrogen, a linear-chain alkyl group with a carbon number of 1-10, a branched-chain alkyl group with a carbon number of 3-8, an alkoxyalkyl group with a carbon number of 2-7, a fluoroalkyl group with a carbon number of 1-10 in which one or two hydrogen atoms are substituted by fluorine atom(s), or an alkenyl group with a carbon number of 2-8,
      Q denotes a halogen atom, or an alkoxy, methanesulfonyl, benzenesulfonyl or p-toluenesulfonyl group,
      X denotes a CN, F, Cl, CF3, CF2Cl, CHFCl, OCF3, OCHF2, OCF2Cl, OCHFCl, R or OR group (wherein R is as defined above),
      Y denotes H or F,
      Z denotes H or F and
      n and m are integers of from 0, 1 or 2 (where n+m = 2).
    5. A method for preparing the silacyclohexane compound as defined in claim 1 characterized by reacting an organometallic reagent of formula
      Figure 00580001
      with a compound of formula
      Figure 00580002
      wherein
      M denotes MgP (P denotes a halogen atom), ZnP or Li,
      R denotes hydrogen, a linear-chain alkyl group with a carbon number of 1-10, a branched-chain alkyl group with a carbon number of 3-8, an alkoxyalkyl group with a carbon number of 2-7, a fluoroalkyl group with a carbon number of 1-10 in which one or two hydrogen atoms are substituted by fluorine atom(s), or an alkenyl group with a carbon number of 2-8,
      Q denotes a halogen atom, or an alkoxy, methanesulfonyl, benzenesulfonyl or p-toluenesulfonyl group.
      X denotes a CN, F, Cl, CF3, CF2Cl, CHFCl, OCF3, OCHF2, OCF2Cl, OCHFCl, R or OR group (wherein R is as defined above),
      Y denotes H or F and
      Z denotes H or F.
    6. A method for preparing the silacyclohexane compound as defined in claim 1 characterized by reacting an organometallic reagent of formula
      Figure 00580003
      with a compound of formula
      Figure 00580004
      wherein
      M' denotes MgP (P denotes a halogenatom), ZnP or B(OY') (Y' denotes H or an alkyl group),
      R denotes hydrogen, a linear-chain alkyl group with a carbon number of 1-10, a branched-chain alkyl group with a carbon number of 3-8, an alkoxyalkyl group with a carbon number of 2-7, a fluoroalkyl group with a carbon number of 1-10 in which one or two hydrogen atoms are substituted by fluorine atom(s), or an alkenyl group with a carbon number of 2-8,
      Q denotes a halogen atom, alkoxy, methanesulfonyl, benzenesulfonyl or p-toluenesulfonyl group,
      X denotes a CN, F, Cl, CF3, CF2Cl, CHFCl, OCF3, OCHF2, OCF2Cl, OCHFCl, R or OR group,
      Y denotes H or F and (wherein R is as defined above)
      Z denotes H or F.
    7. A liquid crystal composition characterized by containing a compound as defined in claim 1.
    8. A liquid crystal display element characterized by containing the liquid crystal composition as defined in claim 7.
    EP94116195A 1993-10-14 1994-10-13 A silacyclohexane compound, a method of preparing it and a liquid crystal composition containing it Expired - Lifetime EP0648773B1 (en)

    Applications Claiming Priority (6)

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    JP281883/93 1993-10-14
    JP28188393 1993-10-14
    JP28188393 1993-10-14
    JP21817094 1994-08-19
    JP21817094 1994-08-19
    JP218170/94 1994-08-19

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    EP0648773A1 EP0648773A1 (en) 1995-04-19
    EP0648773B1 true EP0648773B1 (en) 1999-09-08

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    JPH07304780A (en) * 1994-05-11 1995-11-21 Shin Etsu Chem Co Ltd Silacyclohexanecarbaldehyde compound and production of silacyclohexane-type liquid crystal compound using the same
    US5560866A (en) * 1994-06-22 1996-10-01 Shin-Etsu Chemical Co., Ltd. Process for preparing silacyclohexane compounds
    EP0692485B1 (en) * 1994-07-12 2000-01-05 Shin-Etsu Chemical Co., Ltd. Cyclohexane carbaldehyde compounds and processes for preparing silacyclohexane-based liquid crystal compounds from the carbaldehyde compound
    DE69518294T2 (en) * 1994-10-20 2000-12-21 Shinetsu Chemical Co Novel silacyclohexane compound, a liquid crystalline composition containing it and a liquid crystalline device containing the composition
    US5762826A (en) * 1994-12-22 1998-06-09 Shin-Etsu Chemical Co., Ltd. Liquid crystal composition and a liquid crystal display element which contains it
    US5665271A (en) * 1995-02-13 1997-09-09 Shin-Etsu Chemical Co., Ltd. Silacyclohexane compounds, preparation thereof, liquid crystal compositions comprising the same, and liquid crystal devices comprising the compositions
    KR100234828B1 (en) * 1995-10-16 1999-12-15 카나가와 치히로 Lcd composition and element
    JPH09324178A (en) * 1996-04-01 1997-12-16 Shin Etsu Chem Co Ltd Liquid crystal composition and liquid crystal display element
    US5951913A (en) * 1996-05-22 1999-09-14 Shin-Etsu Chemical Co., Ltd. Liquid crystal compositions comprising silacyclohexane compounds
    KR100378762B1 (en) * 2001-11-13 2003-04-03 Haco Co Ltd Non-woven fabric used in synthetic leather and artificial leather, method for manufacturing the same, and synthetic leather and artificial leather using the same
    KR100534525B1 (en) * 2002-02-01 2005-12-07 주식회사 코오롱 A composite sheet used for artificial leather with low elongation and excellent softness

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    US5547606A (en) 1996-08-20
    DE69420503T2 (en) 2000-04-13
    EP0648773A1 (en) 1995-04-19
    KR950011454A (en) 1995-05-15
    DE69420503D1 (en) 1999-10-14
    KR100232045B1 (en) 1999-12-01

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